1. Field of the Invention
This invention relates generally to composite wood veneer articles having high strength and adapted for severe working without destroying the aesthetically pleasing appearance. More specifically, the invention is adapted to such a composite wood veneer article wherein specific grain orientations are so provided as to accomplish these objectives.
2. Description of the Prior Art
It has been known in situations where improved strength over that provided by solid lumber is required to provide laminated construction wherein alternate layers have grain orientations oriented generally perpendicularly with respect to each other in order to provide increased strength. Conventional plywood is an example of such a laminated construction. U.S. Pat. No. 2,578,781 discloses the use of alternate layers having grains oriented perpendicularly to each other. The plywood units are subsequently formed into tubular articles. Unfortunately, in producing such plywood, strength is increased at a sacrifice of machine workability. Plywood, when carved or scrolled, tends to disintegrate and become unsightly, particularly about the edges. As a result, the beneficial improved strength characteristics of plywood can be employed only in certain end use environments wherein carving or scrolling is not required or unsightly appearance is not objectionable. In some instances, a compromise is effected by performing additional finishing operations upon the unsightly plywood edge in order to attempt to improve its appearance. Such additional finishing involves increased cost and does not generally produce a completely acceptable, aesthetically pleasing appearance.
U.S. Pat. No. 2,291,426 discloses a package wherein alternate plies have grains oriented generally perpendicularly with respect to each other. U.S. Pat. No. 1,625,280 relates to a wooden container and discloses multiple-layer, adhesively bonded constructions having veneer layers with grains oriented perpendicular to each other as well as at intermediate positions.
A further problem with conventional lumber is its susceptibility to undesired chipping and cracking. U.S. Pat. No. 3,908,725 discloses a suggested approach to increasing the modulus of elasticity and modulus of rupture in conventional lumber. This patent discloses severing of lumber into plies of veneer of about 1/4 inch thickness. Three plies of veneer are then adhesively bonded with their grains aligned. The three-ply composite members are then laminated with staggered butt joints so as to produce a piece of laminated lumber one and one-half inch thick or greater multiples thereof. The structure remains, however, merely a reconstructed piece of lumber wherein properties are said to be improved as a result of the multiple laminating and seaming techniques. All grains remain substantially parallel to the longitudinal direction, thereby, in effect, reconstructing the original log grain arrangement.
It has also been known to provide wood layers in combination with plastic materials in order to increase strength. U.S. Pat. No. 3,437,547 discloses a balsa wood assembly having an interposed layer of a polyester. Similarly, U.S. Pat. No. 1,628,886 discloses multiple layer wood construction provided with interposed material such as a pure phenolic condensation product. The wood may be oriented with the grains at differing positions, and high pressure is applied in such fashion that the wood becomes impregnated with the phenolic condensation product, and the wood fibers are compressed, thereby producing unitary, integral mass consisting of compressed wood fibers and penetrated phenolic condensation product. This is to be distinquished from constructions wherein distinct wood veneer layers would remain essentially intact and are merely adhesively bonded to each other.
In U.S. Pat. No. 3,055,065 there is disclosed flexible flooring made of hardwood veneer. It is contemplated that the flooring will be secured to an underlying rigid material which will provide the desired reinforcement, strength and floor rigidity. The flooring may take the form of a single, flexible ply or a two-layer ply having grain orientation offset by a relatively small amount.
U.S. Pat. No. 2,334,619 discloses a tubular wound multiple veneer article fabricated by winding, as by spiral winding, with or without cross winding.
There remains, therefore, a need for a wood article having increased strength and resistance to chipping and cracking as compared with solid lumber as well as the ability to undergo severe carving, scrolling and fine detail work, while preserving an aesthetically desirable appearance and avoiding breaking, flaking and undesired edge disintegration.